Compact enclosure for interchangeable SONET multiplexer cards and methods for using same

ABSTRACT

A compact enclosure for interchangeable SONET multiplexer cards and a method for using the same. The present invention further provides a compact enclosure for receiving one or more reduced size SONET multiplexer cards having front panel access to electrical and optical connectors, along with other cards such as DS1-DS3 multiplexer cards and wave division multiplexing cards, which is adapted for use in a reduced size enclosure, and a method for using the same.

CROSS REFERENCE TO RELATED APPLICATIONS

Related subject matter is disclosed in co-pending U.S. patentapplication Ser. No. 10/448,464 of Bruce Lipski et al., filed even dateherewith, entitled “Apparatus and Method for Increasing Optical Densityof SONET Multiplexer Using Integral Components”; in co-pending U.S.patent application Ser. No. 10/448,453 of Bruce Lipski et al., filedeven date herewith, entitled “SONET Multiplexer Having Front PanelAccess to Electrical and Optical Connectors and Method for Using Same”;and in co-pending U.S. patent application Ser. No. 10/488,461 of BruceLipski et al., filed even date herewith, entitled “Apparatus And MethodFor Automatic Provisioning of SONET Multiplexer”; the entire contents ofeach of these applications being expressly incorporated herein byreference.

FIELD OF THE INVENTION

The present invention relates to a compact enclosure for interchangeableSONET multiplexer cards and a method for using the same. Moreparticularly, the present invention relates to a compact enclosure forreceiving one or more reduced size SONET multiplexer cards having frontpanel access to electrical and optical connectors, along with othercards such as DS1-DS3 multiplexer cards and wave division multiplexingcards, and a method for using the same.

BACKGROUND OF THE INVENTION

As the demand for high bandwidth, high bit rate communications increases(e.g., to accommodate multimedia applications, in particular), fiberoptics technology is rapidly advancing to supply the capacity. SONET(i.e., Synchronous Optical Network) is the communication hierarchy thathas been specified by the American National Standards Institute (ANSI)as a standard for a high-speed digital hierarchy for optical fiber.SONET defines optical carrier (OC) levels and electrically equivalentsynchronous transport signals (STSs) for the fiber-optic basedtransmission hierarchy. The SONET standard is described in more detailin ANSI T1.105 and T1.106, and in Bellcore Telecordia GenericRequirements GR-253-CORE and GR-499-CORE, which are incorporated hereinby reference.

Before SONET, fiber optic systems in the public telephone network usedproprietary architectures, equipment, line codes, multiplexing formatsand maintenance procedures. The users of this equipment (e.g., RegionalBell Operating Companies and inter-exchange carriers (IXCs) in theUnited States, Canada, Korea, and Taiwan, among others countries)desired standards such as SONET so they could employ equipment fromdifferent suppliers without experiencing incompatibility problems.

SONET defines a technology for carrying many signals of differentcapacities through a synchronous, flexible, optical hierarchy using abyte-interleaved multiplexing scheme to simplify multiplexing andprovide end-to-end network management. The base signal in SONET is aSynchronous Transport Signal level-1 (STS-1) which operates at 51.84Megabits per second (Mbps). Higher-level SONET signals are summarized inthe following table:

TABLE 1 SONET Hierarchy Signal Bit Rate Capacity STS-1, OC-1  51.840Mb/s 28 DS1s or 1 DS3  STS-3, OC-3  155.520 Mb/s 84 DS1s or 3 DS3sSTS-12, OC-12  622.080 Mb/s 336 DS1s or 12 DS3s STS-48, OC-48 2488.320Mb/s 1344 DS1s or 48 DS3s  STS-192, OC-192 9953.280 Mb/s 5376 DS1s or192 DS3s STS-768, OC-768 39813.12 Mb/s 21504 DS1s or 768 DS3s 

Thus, each SONET STS-N electrical signal has a corresponding OC-Noptical signal. The OC-N signals are created by converting the STS-Nelectrical signal to an optical signal. The SONET standard establishes amultiplexing format for using any number of 51.84 Mbps signals asbuilding blocks. For example, an OC-3 (Optical Carrier, Level 3) is a155.52 Mbps signal (i.e., 3 times 51.84 Mbps), and its electrical signalcounterpart is referred to as an STS-3 signal. The STS-1 signal carriesa DS3 signal or a number of DS1 or other lower level signals. A SONETSTS-3 signal is created by concatenating STS-1 signals.

Telecommunication equipment at central offices (COs), remote terminals(RTs), wireless communication cell sites and other equipment locationsis frequently deployed as one or more multi-shelved bays with multipleshelves, wherein each shelf is configured to receive a plurality ofcommunications cards. A backplane is provided in each bay forcommunication between its cards and shelves, as well as for interbaycommunication. One of the more common types of equipment to be found atthese equipment sites is SONET multiplex equipment which takeslower-rate (tributary) signals, such as DS1 (1.5 Mbps), DS3 (45 Mbps),OC-1 (51.84 Mbps), or OC-3 (155.52 Mbps), and time division multiplexesthem into a higher-rate signal such as OC-3 or OC-12 (622.08 Mbps). TheSONET multiplex equipment also performs the corresponding demultiplexfunction of recovering the lower rate tributary signals from an incominghigher-rate signal.

Telecommunications companies are eager to provide as much performance aspossible from their existing infrastructure. Their telecommunicationssystems are primarily based on the DS1 electrical signal hierarchy thatuses DS0 data. A DS1 signal is comprised of 24 multiplexed DS0 voice ordata channels. To provide capacity that meets the afore-mentioned demandfor more bandwidth and high bit rates, telecommunications companies needequipment that is based on a higher data rate such as DS3 in which DS1signals are the base signal for data channel multiplexing, as opposed toDS0 signals.

Problems with existing equipment managing DS3 traffic, however, arenumerous. For example, DS3 hierarchy-based equipment requires more bayand shelf space in CO, RT, cell sites and other locations whereequipment space is already a limited commodity, where bays and shelvesare already crowded (e.g., many shelf card slots are filled with acard), and where room to add equipment with new features is very limitedor essentially nonexistent.

In addition, previous generations of SONET and asynchronous multiplexequipment have dedicated fixed portions of an equipment shelf todifferent types/rates of services. For example, separate portions of theshelf are typically reserved for DS1, DS3, and OC3 interface units.Dedicating specific portions of the shelf to specific service typesreduces the flexibility of the shelf, and typically leaves wasted shelfspace for any given application.

Also, access to the optical connectors on existing multiplexer cards istypically on the front of a card, while access to the electricalconnectors is on the back of the shelf. In equipment locations werespace is limited, it can be difficult for human operators to gain accessto the backs of card slots in a shelf of an equipment bay. A needtherefore exists for SONET multiplexer equipment having a reduced formfactor, with nondedicated card slots, and with front panel access toboth electrical connectors and optical connectors.

To illustrate these disadvantages of existing SONET multiplex equipment,reference will now be made to FIG. 1 which illustrates a Fujitsu SONETmultiplexer 10 (i.e., model FLM-150). The Fujitsu multiplexer 10requires an entire shelf in a communications bay and dedicated cardslots. For example, several cards are needed for DS1 to DS3multiplexing, several cards are needed for DS3 to OC3 processing, and soon. Thus, a need exists for a SONET multiplexer having standardfunctionality, yet requiring less equipment space.

The Fujitsu multiplexer 10 is not easily set up or provisioned. TheFujitsu multiplexer 10 is designed to be everything to everyone in theoptical communications environment. Since it is not designed to becompatible with any one particular system, it provides hundreds ofchoices to the user and must be substantially configured by a useroperating a provisioning application on a computer (e.g., a personalcomputer or PC) before it can even run data through it. Theinstallation, set up and provisioning manual for the Fujitsu multiplexer10 is long and considerable training is needed for the user to be ableto configure and operate the unit. Further, after such a lengthy andinvolved configuration phase, the unit may not be subsequently easilyreprovisioned to accommodate a change in the configured data paths. Thisaspect of the Fujitsu multiplexer 10 renders it very cumbersome. Thus, aneed exists for SONET multiplexing equipment that requires minimal setup and provisioning, and minimal or no user training. Further, a needexists for SONET multiplexing equipment that does not require connectingthe equipment to a computer for provisioning, and that automates much ofthe provisioning process to simplify it for the user. In addition, aneed exists for SONET multiplexing equipment that simplifiesprovisioning to allow reconfiguration of the equipment for flexible use.

Also, to use the Fujitsu multiplexer 10 in different applications suchas a drop or drop and continue (e.g., ring) application requires moreplug-in units, which increases cost, and requires more set up andprovisioning. A need exists for a SONET multiplexer that can be deployedin different applications with greater functionality, little or noprovisioning, and a minimal number of units to minimize cost andmalfunctions due, for example, to failed electronics. For example, iffour Fujitsu multiplexers units were to be deployed in a ringconfiguration, the Fujitsu units would require substantial provisioningto instruct the unit regarding which data paths are being dropped andcontinued and how to cross-connect at each node, as well as alarmconditions, among other configuration data. Thus, a need exists forSONET multiplexing equipment that simplifies provisioning to allowconfiguration of the equipment for flexible use in differentapplications.

Providing redundancy of optical paths can present a problem where thereis limited equipment space since additional circuit packs are used incompeting SONET multiplexers. Reference is now made to FIG. 2, whichdepicts another existing SONET multiplexer that is available fromAdtran, Inc. The Adtran SONET multiplexer is the Total Access OPTI-3model which converts OC3 to three DS3s and consists of a rack-mountedshelf device.

SONET multiplexers generally provide redundancy of data paths to enablecontinued transmission of data after an optical path failure. Withcontinued reference to FIG. 2, a conventional SONET system 12 employsplural multiplexers 20, 20′ and 22, 22′ at each of the nodes 14 (e.g., acentral office) and 16 (e.g., a remote terminal or subscriber premise),respectively. A path 18 is selected as the primary path and a secondarypath 18, is used in the event of primary path failure. In a 1:nredundancy system, wherein n is an integer, n paths are available andn−1 paths are used with the remaining path being a spare. A 1:n systemrequires communication between the multiplexers to establish whichpath(s) are in use and which path(s) are reserved for use following apath failure. In a 1+1 redundancy system, the path is selected based onwhichever of the two paths is working and communication between themultiplexers regarding the selected redundant path is required.

Configuring a SONET system with redundancy using the Adtran multiplexerrequires at least four multiplexers 20, 20′, 22, 22′ (i.e., two per nodefor two optical paths between the nodes). This redundant configurationis disadvantageous over a system having only a single optical pathbetween two multiplexers, and therefore no redundancy, because itrequires twice the equipment space and twice the cost for the extra twomultiplexers. Further, the redundant system is less reliable in terms ofthe increased likelihood for electronics failure or equipment failuredue to heat, for example, due to the additional multiplexer electronics.A need exists for a SONET multiplexer that provides redundancy whileminimizing equipment space and cost and maximizing reliability.

The limitations of the known systems discussed above also render thosesystems difficult to use in 3^(rd) Generation (3G) wireless services. Inparticular, the costs and complexities of delivering the known DS3systems to cell cites have limited their ability to be deployed in 3Gsystems. For example, severely limited cabinet or hut space wouldrequire expensive new enclosures and power supplies to run the known DS3systems. Furthermore, because 3G systems require upgrades to numerouscell cites, costs related to the time consuming provisioning andinterconnect of traditional SONET equipment expand rapidly. Alternativefiber optic systems that can be used are either exorbitantly expensiveor limited to point-to-point rather than efficient drop-and-continuetopologies. In addition, future growth has been limited by largeup-front equipment investments or products that are limited tosupporting only 3 DS3s. Hence, a need exists for a small, fast, easy touse SONET and DS3 system that is scalable and is capable of supportingintegral drop-and-continue applications.

SUMMARY OF THE INVENTION

The present invention provides a compact enclosure for interchangeableSONET multiplexer cards and a method for using the same.

The present invention further provides a compact enclosure for receivingone or more reduced size SONET multiplexer cards having front panelaccess to electrical and optical connectors, along with other cards suchas DS1-DS3 multiplexer cards and wave division multiplexing cards, whichis adapted for use in a reduced size enclosure, and a method for usingthe same. More particularly, the compact enclosure assembly comprises anenclosure having a plurality of openings therein, each adapted tointerchangeably receiving a reduced size SONET multiplexer cardconfigured in a standard Type 400 mechanics circuit board arrangement,and a first of the openings being capable of interchangably receiving areduced size SONET multiplexer card configured in a standard Type 400mechanics circuit board arrangement and another card. The compactenclosure assembly is adapted to attach to an outside of a supportenclosure, or to be received in a larger enclosure. In one embodiment,the enclosure has a height of about 5.9 inches, a width of about 4.1inches, and a depth of about 7.3 inches.

In one embodiment, the enclosure has two of the openings therein, thefirst of which having a larger width than the other and being capable ofreceiving a reduced size DS 1-DS3 multiplexer card, or the reduced sizeSONET multiplexer card and a wave division multiplexing card at the sametime. A fan can be mounted to the enclosure. Also, a cable fibermanagement assembly can be mounted to the enclosure for storing a cablefiber. A cable guard can be mounted at a front end of the enclosure.

The enclosure is distinguished by the use of rear connectors to onlyprovide power and collect alarms from plug-in cards so that a multitudeof different plug-in cards of various functions can be plugged into theenclosure in any available space. Prior SONET or DS3-DS1 multiplexingequipment required either dedicated shelves or specific card slots in ashelf to be used for specific applications.

Another unique capability of the embodiments of the invention is theability to accept plug-in Wave Division Multiplexing cards. In the past,WDM units were mechanically attached to shelves or racks in use and havebeen unavailable as plug-in cards. The embodiment of the invention'sability to accept a plug-in card in any available position permits thisnew and more convenient configuration of WDM technology in a plug-incard. Those skilled in telecommunication requirements will recognizethat the plug in card is required to provide proper grounding of the WDMplug-in card.

BRIEF DESCRIPTION OF THE DRAWINGS

These and other objects, advantages and novel features of the presentinvention will be readily appreciated from the following detaileddescription when read in conjunction with the accompanying drawings, inwhich:

FIG. 1 depicts a conventional SONET multiplexer;

FIG. 2 depicts conventional SONET multiplexers configured for opticalredundancy;

FIG. 3 is a perspective view of a reduced-sized enclosure for providingSONET and other multiplexing capabilities according to an embodiment ofthe present invention;

FIG. 4 is a front perspective view of the enclosure shown in FIG. 3;

FIG. 5 is a rear perspective view of the enclosure shown in FIG. 3;

FIG. 6 is a front view taken along lines 4—4 in FIG. 4 showing theinternal connectors of the enclosure;

FIG. 7 is a left-side view of the enclosure shown in FIG. 4;

FIGS. 8 a and 8 b are rear views of the enclosure shown in FIG. 4;

FIG. 9 is a top view of the enclosure shown in FIG. 4;

FIG. 10 is a bottom view of the enclosure shown in FIG. 4;

FIG. 11 is a perspective view of a O3-3D3 module used in the enclosureshown in FIGS. 3 and 4;

FIG. 12 is another perspective view of the 03-3D3 module shown in FIG.11;

FIG. 13 is a right-side view of the 03-3D3 module shown in FIGS. 11 and12;

FIG. 14 is a front view of the 03-3D3 module shown in FIGS. 11 and 12;

FIG. 15 is a plan view of a lower circuit board contained in the O3-3D3module shown in FIGS. 11 and 12;

FIG. 16 is a plan view of an upper circuit board contained in the O3-3D3module shown in FIGS. 11 and 12;

FIG. 17 is a perspective of the D3-28D1 module used in the enclosure asshown in FIG. 3;

FIG. 18 is a right-side view of the D3-28D1 module shown in FIG. 17;

FIG. 19 a is a front view of the D3-28D1 module shown in FIG. 17;

FIG. 19 b is a front view of the D3-14D1 module, which is similar to theD3-28D1 module but has only a single 64 pin connector;

FIG. 20 is bottom view of the D3-28D1 module shown in FIG. 17;

FIG. 21 is a functional block diagram of the D3-28D1 module shown inFIG. 17;

FIG. 22 is a perspective view of a WDM-1 coupler module that can be usedwith the assembly as shown in FIG. 3;

FIG. 23 is a side view of the WDM-1 module shown in FIG. 22;

FIG. 24 is a front view of WDM-1 module shown in FIG. 22;

FIG. 25 is a perspective view of a WDM-2 coupler module that can be usedwith apparatus shown in FIG. 3;

FIG. 26 is a right-side view of the WDM-2 module shown in FIG. 25;

FIG. 27 is a front view of WDM-2 module shown in FIG. 25; and

FIGS. 28 a-f illustrates examples of optional module configurations thatcan be used in the assembly shown in FIG. 3.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

FIG. 3 is a perspective view of a reduced-size assembly 100 for mountingSONET and other multiplexing equipment to achieve DS3 and othermultiplexing capabilities according an embodiment of the presentinvention. As described in more detail below, the assembly 100 iscapable of receiving different combinations of modules, such as, but notlimited to, O3-3D3, O3-3D3P, DS3 Express, D3-14D1, D3-28D1, and WDMmodules, depending on the type of application and the types ofinterfaces required.

In the example shown in FIG. 3, a O3-3D3 module 102 and a D3-28D1 module104 are removably installed in the assembly 100. As shown in FIG. 4, theassembly 100 includes an enclosure assembly 106 that can be made ofaluminum, anodized steel or any other suitable material. In thisexample, the enclosure assembly 106 includes an enclosure 108 on top ofwhich is mounted a fan 110 for cooling the modules inserted in theenclosure 108. The enclosure 108 has a cable fiber management assembly112 for keeping a maintenance loop of fiber optic or coaxial cable (notshown) since there is normally cable slack and conventional equipmentlacks this capability to store the slack, relying upon external slackstorage instead. The enclosure 108 further includes optional cable guard114 that can be installed on the enclosure 108 by screws, rivets or thelike to prevent mechanical cable damage. The enclosure also includes amounting angle 116 for assisting in the mounting of the enclosure in alarger rack (not shown). The enclosure includes provisioning for wallmounting as well.

As shown in FIGS. 4 and 6, the front of the enclosure 106 has openings118 and 120. As shown in FIG. 6 in particular, three connectors 122 aremounted inside the openings 118 and 120 on the rear panel of theenclosure 106, and are electrically connected to external connectors 124as shown in FIGS. 5 and 7 through 10. Accordingly, as discussed in moredetail below, when the modules are loaded into openings 118 and 120, theconnectors on the back ends of the modules mate with the respectiveconnectors 122 in the enclosure 108, and thus provide electricalconnectivity to the external connectors 124.

As shown in FIGS. 6-9, in this example, the enclosure 108 has an overallheight of 5.878 inches (about 5.9 inches) without the fan 110, and theenclosure assembly 106 has an overall height of 7.000 inches (about 7.0inches) with the mounted fan 110. The enclosure 108 has an overall widthof 6.147 inches (about 6.1 inches) taking into account the fibermanagement assembly 112 and the mounting angle 116, an overall depth of7.30 inches (about 7.30 inches), and an overall width of 4.147 inches(about 4.1 inches) without the fiber management assembly 112 andmounting angle 116. As indicated, the fiber management assembly 112projects 1.000 inches (about 1 inch) from the left side of the enclosure108, and is 1.743 inches in diameter, and the mounting angle 116projects 1.000 inches (about 1 inch) from the right side of theenclosure 108. The slots 117 in the mounting angle 116 are spaced 1.00inches apart as indicated in FIG. 6. Accordingly, the dimensions of theenclosure assembly 106 enable the assembly 100 to be easily deployed,for example, at cell sites in a 3G network. The enclosure assembly 106can be rack mounted as are conventional assemblies, or can be mounted onpractically any suitable surface, such as at the top or side of a largerassembly, a wall of a room, on a table or desk top, and so on. It isnoted that all dimensions given above can be viewed as approximate.However, in this embodiment, the dimensions can be viewed as the maximumdimensions which should not to be exceeded.

FIGS. 11-16 show a more detailed view of the O3-3D3 module 102 as shownin FIG. 3. Specifically, as indicated, the module 102 includes a faceplate 126 to which are mounted a plurality of coaxial connectors 128 anda plurality of duplex optical fiber connectors 130. It is noted thatunlike previous modules, the coaxial connectors 128 and the opticalfiber connectors 130 are mounted on the face plate 126 to provide easieraccess to them without having to remove the module 102 from the assembly100. The module 102 further includes a card extractor 132 that allowscase in removing the module 102 from the assembly 100. As indicated inFIGS. 13 and 14, the module 102 has an overall height of 5.590 inches(about 5.6 inches), and overall width of 1.403 inches (about 1.4inches), and an overall depth of 6.027 inches (about 6 inches).

As can be appreciated by one skilled in the art, the O3-3D3 module 102is designed to derive three DS3 circuits from an OC3 synchronous opticalnetwork (SONET) 1550 nm or 1310 nm optical facility, and is configuredto be inserted into opening 118 or 120 of enclosure assembly 106 (seeFIG. 4). Specifically, due to its standard Type 400 mechanics circuitboard arrangement, the O3-3D3 module 102 as well as similar DS3-to-DS1,WDM and DS3 Express modules can be inserted into any available cardslot. As shown in FIGS. 15 and 16, in particular, the face plate 126 ismounted to two circuit boards 132 and 134. The main or lower circuitboard 132 shown in FIG. 15 comprises a field programmable gate array(FPGA) U16 indicated at 136, two SONET synchronizers U8 and U12indicated at 138 and 140, respectively, a SONET overhead terminator U7indicated at 142, switches 144 and 146, an optical transceiver U11indicated at 148 which is connected to an optical fiber connector 130,and an optical transceiver U15 indicated at 150 which is connected tothe other optical fiber connector 130. The main or lower circuit board132 also comprises OC3 status LEDs 152 and 154, and a UNIT status LED156.

The upper board 134 shown in FIG. 16 comprises a Mapper U5 indicated at158, a Triple DS3 Line Interface Unit U4 indicated at 160, a DS3 jitterattenuator U8 indicated at 162, and the coaxial connectors 128 which actas DS3 ports. The upper board 134 also comprises DS3 status LEDs 164,166 and 168, and switches 170, 172, 174, 176, 178 and 180. Additionalcomponents such as heat sinks, the connector between the boards 132 and134, the card connector, and other circuits that support the operationof the boards 132 and 134 are provided on the boards 132 and 134.Further details of the operation of module 102 are described in theabove-mentioned copending applications filed concurrently herewith.Briefly, an optical signal is converted to an electrical format by theoptical transceiver 148. A clock data recovery unit or CDRU (not shown)obtains the receive clock frequency and receive path optical rate toseparate the clock and data and provide the data to an optical lineinterface unit. The output of the transceiver 148 is processed todetermine the boundaries between each bit. This processing is performedby the SONET synchronizers 138 and 140. The data is accented by theSONET overhead terminator 142 which finds the start of each 125microsecond frame and extracts certain bytes called overhead. Overheadis data in the SONET stream which is not the customer's data. It isadditional data used to perform administrative functions such as switchto protect operations. The SONET overhead terminator 142 uses a pointermechanism to locate the bytes within the SONET stream which are customerdata. The module 102 of the present invention can be provided with anoptional second OC3 port which can be used to provide protectionswitching. The optical transceiver 150, a CDRU, and optical lineinterface unit support the second OC3 port. These devices operate withrespect to the second OC3 feed in the same manner as stated above inconnection with the primary optical transceiver 148, CDRU, and opticalline interface unit and the primary OC3 feed. The pointer and thecustomer data are handed to the mapper 158 where it is divided intothree DS3 streams. The triple DS3 LIU 160 converts three streams ofdigital data into three standard analog interfaces. The module 102components are bi-directional. The DS3 LIU 160 accepts three analogsignals and converts them to digital format. The mapper 158 accepts thethree digital streams and converts them to a single digital stream inthe SONET format. The SONET overhead terminator 142 appends the overheaddata to the data received from the mapper 158. Each SONET synchronizer138, 140 provides the appropriate drive to the corresponding opticaltransceivers 148 and 150.

As can be appreciated from the above, the O3-3D3 module 102 is providedwith a number of advantageous features such as three coaxial connectors128 (DS3 ports), and two optical fiber connectors 130 (OC3 ports) on theface plate. Thus, a user has easy access to the coaxial connectors 128and optical fiber connectors 130 without having to remove the module 102from the enclosure assembly 106, or without having to access the coaxialconnectors 128 and optical fiber connectors 130 via the rear of theenclosure assembly 106. Accordingly, coaxial jumpers can be used tocouple the coaxial connectors 128 to coaxial connectors on other modulesas explained in more detail below. This capability is made possiblebecause the enclosure does not have dedicated card slots and the unitshave faceplate connectors. Standard DS3 75-ohm BNC connections can beused as the coaxial connectors 128, and standard fiber SC interfaceconnectors can be used as the optical fiber connectors 130.

As described in more detail in the above-mentioned copendingapplications, the O3-3D3 module 102 is configured with adrop-and-continue ring capability with or without protection switchingthat is substantially easier to use and less costly than existingmultiplexers such as those described above. Whereas existing multi-shelfand/or multi-card multiplexers require substantial configuration andprovisioning to achieve merely an operable data path, the O3-3D3 moduleprovides exceptionally simple plug-and-play installation and use invarious applications. The O3-3D3 module 102 uses standard Type 400mechanics to permit installation in the enclosure assembly 106 asdiscussed above, as well as in inexpensive wall, shelf, orself-contained housings within a central office (CO), digital loopcarrier (DLC), or remote terminal (RT) facilities or customer-premisesequipment (CPE). The O3-3D3 module 102 is also climate-hardened forunrestricted deployment in outside plant (OSP) cabinets.

It should also be noted that the O3-3D3 module 102 is provided with 1310nm or 1550 nm optics that can be used with Wave Division Multiplexing(WDM) couplers, such as those depicted in FIGS. 21-26 and described inmore detail below. The O3-3D3 module has either medium-range optics toeconomically support fiber facilities of up to 40 kilometers, orlong-range optics to support extended range (ER) applications up to 80kilometers, as described below. Furthermore, the O3-3D3 module 102employs comprehensive and continuous monitoring of the optical local andremote loss of frame, loss of signal, out of frame, loss of pattern,loss of pointer, optical degradation, blown fuse, unit failure, and lossof power with universal contact closure alarm reporting. The O3-3D3module is also provided with a remote alarm indication signal andloopback capability for comprehensive network and maintenancemonitoring, and allow for fiber-to-fiber operation with traditional OC3SONET multiplexers.

Further details of the D3-28D1 module 104 shown in FIG. 3 will now bedescribed with respect to FIGS. 17-20. Specifically, the module 104includes a faceplate 190 to which are mounted a plurality of 75-ohmcoaxial connectors 192, a connector 194, a plurality of 64 pin AMP™connectors 196, and a plurality of cards 197 a, 197 b and 197 c. Thefaceplate 190 also includes a plurality of LEDs 198-1, 198-2 and 198-3indicating different statuses of the operation of the module 104, suchas DS1, DS3, and UNIT status, and a card extractor 200 which allows forease of removing the module 104 from the assembly 100. Thus, a user haseasy access to the coaxial connectors 192 and other connectors withouthaving to remove the module 102 from the enclosure assembly 106, orwithout having to access the connectors via the rear of the enclosureassembly 106.

As indicated, the faceplate 190 has an overall height of 5.590 inches(141.98 mm), and overall width of 2.25 inches (57.25 mm). The module 104has an overall depth of 6.57 inches (153.858 mm), and the cards eachhave an overall height of 5.59 inches (141.86 mm). The card extractor200 extends 0.58 inches (14.77 mm) from the front surface of the faceplate 190. Also, the individual cards have respective heights of 4.94inches (125.57 mm), 5.04 inches (127.93 mm), and 5.45 inches (138.32mm). Card 197 c and middle card 197 b are separated by 0.58 inches (14.8mm), and card 197 a and middle card 197 b are separated by 0.78 inches(19.8 mm). It is noted that all dimensions given above can be viewed asapproximate. However, in this embodiment, the dimensions can be viewedas the maximum dimensions which should not to be exceeded.

As can be appreciated by one skilled in the art, the D3-28D1 DS1 module104 multiplexes 28 DS1 signals into a DS3 signal and demultiplexes a DS3signal to 28 DS1 signals. It is also noted that the module 104 can beconfigured as a D3-14D1 DS1 module which multiplexes 14 DS1 signals intoa DS3 signal and demultiplexes a DS3 signal to 14 DS1 signals. TheD3-28D1 DS1 module 104 provides two kinds of management interfaces,namely, the craft port connector 194 on the front panel connects to a PCusing VT-100 terminal emulation, and the RS-232 asynchronous networkmanagement port on the backplane uses TL-1 messages for maintenance anddiagnostic functions. The D3-28D1 DS1 module 104 thus providesindustry's smallest, self-contained DS3 to DS1 multiplexer. The module104 provides drop-and-continue capability optimized for efficientaccess. For example, a single digital cross-connect system (DCS) or nextgeneration digital loop carrier (NGDLC) DS3 port can deliver four DS1sto seven different sites. The module 104 also provides available supportfor standard in-band DS1 NIU loopbacks as well as integral T1 repeaters(“SJ” versions) to eliminate the need for external “smart jacks” andconnection to standard T1 lines of up to 6000 feet, and availablesupport for in-band loopback codes issued on either the DS1 side or theDS3 side to suit comprehensive network diagnostics. The module 104further has outside plant (OSP) climate hardening, and robust lightningprotection to withstand the rigors of cell site applications, such as in3G networks.

The module 104 further provides for OSP, central office (CO), andcustomer-premises equipment (CPE) mountings with provision forcomplementary O3D3 and O3-3D3 miniature synchronous optical network(SONET) multiplexers and wave division multiplexer (WDM) units. Themodule 104 also provides simple, intuitive craft port provisioning andpre-assigned defaults for common applications to assure fast,trouble-free turn-up, a full-time TL-1 communication link, comprehensiveperformance monitoring (PM) that eliminates the cost of external DS3NIUs and delivers single-point platform diagnostics. Alternatively, themodule 104 can be configured as a type 400 mechanics 14 DS1 version,instead of a Type 600 mechanics 28 DS1 version as shown.

FIG. 21 is a functional block diagram of D3-28D1 module 104 discussedabove. As shown, up to 28 DS1 circuits are combined into a single DS3signal. The D3-28D1 performs multiplexing transparently (no modificationof DS1 payload). FIG. 3 shows a functional block diagram. The DS3interface is compliant with GR-499-CORE Section 9.6, Table 9-15. Itdetects alarm indication signal (AIS), remote defect indicator (RDI),and IDLE signal per GR-499-CORE Sections 10.5, 18.2, and 18.3. The DS3transmitting pulse template meets T1.404. The interface supports bipolarwith 3-zero substitution (B3ZS) line code and M-Frame and C-bit parityframing formats.

Each DS1 is provisioned for alternate mark inversion (AMI) or bipolarwith 8-zero substitution (B8ZS) line coding. Each DS1 is transparent tosuperframe (SF) and extended superframe (ESF) formats. Each DS1 pulsetemplate meets ANSI T1.102. Each DS1 port is provisioned for digitalsignal cross-connect (DSX-1) type interface (short haul), with linebuild-outs (LBOs) appropriate to service line lengths from 0 to 655feet. Each DS1 port of the DS-28D1SJ and DS-14D1SJ may also beprovisioned for long-haul applications; the transmit attenuation inthese versions is also selectable for 0, 7.5, 15, or 22.5 dB. TheD3-28D1 detects loss of signal (LOS), all ones (AIS), and line codeviolations (LCVs) for each DS 1 on the low-speed (DS1) side. There aretwo alarm relays on the D3-28D1. The DS3 alarm contacts close for a DS3failure. The DS1 alarm contacts close for LOS or loss of frame (LOF) onany IN-SERVICE DS1 port. Both DS3 and DS1 alarm contacts close for aloss of power or unit failure.

The front panel of the D3-28D1 module 104 provides connection to the DS3and DS1 signals as well as the craft port. As discussed above, LEDs198-1, 198-2 and 198-3 show connector and unit status. Each DS1connector has 14 transmit (Tx) pairs and 14 receive (Rx) pairs. Thefront-panel DB-9 communications interface is an asynchronous VT-100serial port. The craft port 194 operates at 9600 baud with 8 bits ofdata, no parity, and 1 stop bit.

As discussed above, the assembly 100 is capable of receiving O3-3D3modules 102 and D3-28D1 module 104. In addition, and as discussed inmore detail below, the assembly 100 is capable of receiving one or moreWave Division Multiplexing (WDM) modules as shown in FIGS. 22-27. Thatis, FIGS. 22-24 illustrate an example of a WDM-1 module 210. The module210 includes a faceplate 212 to which are mounted a single fiberconnector 214 and a duplex fiber connector 216. Also, a card extractor218 is mounted to the front panel 212 to allow for ease of removing themodule 210 from the assembly 100, and a protective cover 219 is providedfor protection. The printed circuit board 214 that is mounted in themodule 210 has contacts 220 at its back end which mate with a respectiveconnector 122 inside the enclosure assembly 106 (see FIG. 6) of theassembly 100 when the module 210 is loaded into the enclosure 106. Asshown in FIGS. 22-24, the module 210 has an overall height of 5.590inches, and overall width of 0.711 inches, and an overall depth of 6.072inches. It is noted that all dimensions given above can be viewed asapproximate. However, in this embodiment, the dimensions can be viewedas the maximum dimensions which should not to be exceeded.

FIGS. 25-27 illustrate details of a WDM-2 coupler module 230 that can beinstalled in the assembly 100. As indicated, the module 230 include aface plate 232 to which are mounted a plurality of single fiberconnectors 234 and duplex fiber connectors 236. A card extractor 238 isalso mounted to the front panel 232 to allow for ease of removal of themodule 230 from the assembly 100, and a protective cover 239 is providedfor protection. A printed circuit board contained in the module 230 hascontacts 240 at its back end which mate with a respective connector 122in enclosure assembly 106 (see FIG. 6) of assembly 100 when the module230 is inserted into the enclosure assembly 106. As indicated, thedimensions for module 230 are similar to those for module 210.

As can be appreciated by one skilled in the art, the WDM-1 module 210and WDM-2 module 230 in this example are 200 Mechanics® Wave DivisionMultiplexing Couplers. The WDM-1 module 210 is a single coupler forsingle fiber transport between a 1310 nm O3D3 or O3-3D3 at one end of acircuit and a 1550nm O3D3 or O3-3D3 at the other end of a circuit. TheWDM-2 module 230 is a dual coupler for two fiber switch-to-protectapplication, and can also increase the capacity over fibers already inuse by legacy optical multiplexers. When used with an O3D3 multiplexer,the WDM-1 and WDM-2 modules permit a single fiber to carry both transmitand receiver payloads to address fiber exhaustion, and serveapplications such as support of digital subscriber line (DSL) deliveryfrom legacy carrier systems. The WDM-1 and WDM-2 modules 210 and 230thus provide simple hand-in-glove use with O3D3 and O3-3D3 modules asdiscussed above. The 200 Mechanics® configuration permits installationin conventional, inexpensive, central office (CO) digital loop carrier(DLC) remote terminal (RT) or customer-premise equipment (CPE) wall,shelf or self-contained housing. The WDM-1 and WDM-2 modules 210 and 230also are climate-hardened for unrestricted deployment in outside plant(OSP) cabinets, and perform derivations of 1310 nm and 1550 nmsingle-node channels from a single fiber. The printed circuit boardshroud prevents fibers from becoming entangled in other equipment. Themodules 210 and 230 further include SC bulkhead OC3 connectors, requireonly simple installation without special mounting plates or brackets,and meet GR-2899-CORE criteria in O3D3, O3-3D3 and similar applications.

As discussed above, the enclosure 108 is capable of receiving variouscombinations of the types of modules described above. Several examplesof this configuration are shown in FIGS. 28 a-f. FIG. 28 a shows anempty enclosure assembly 106 as shown in FIG. 6. As shown in FIG. 28 b,the assembly 100 can receive a single O3-3D3 module 102, or similarmodules O3D3 and O3-3D3P, as well as one D3-28D1 module 104. As shown inFIG. 28 c, the assembly 100 can receive any of the WDM modules (i.e.,WDM-1 or WDM-2) 210 or 230 as discussed above, as well as module 102 anda D3-14D1 module 104-1 as discussed above. As shown in FIG. 28 d, theassembly 100 can receive two O3-3D3 modules 102, and anyone of the WDM-1or WDM-2 modules 210 or 230 as indicated. As shown in FIG. 28 e, theassembly 100 can receive two DS3 Express modules 105. These modules,permit a high speed DS3 circuit to be carried over four standard twistedpair cables. As shown in FIG. 28 f, the assembly 100 can receive aD3-28D1 module 104, and a DS3 Express module 105.

Although only a few exemplary embodiments of the present invention havebeen described in detail above, those skilled in the art will readilyappreciate that many modifications are possible in the exemplaryembodiments without materially departing from the novel teachings andadvantages of this invention. Accordingly, all such modifications areintended to be included within the scope of this invention as defined inthe following claims.

1. A compact enclosure assembly for receiving at least one reduced sizeSONET multiplexer card, the enclosure assembly comprising: an enclosurehaving a plurality of openings therein, each dimensioned tointerchangeably receive a reduced size SONET multiplexer card configuredto fit in a card slot of a telecommunications bay equipment shelf, and afirst of the openings being capable of interchangably receiving saidreduced size SONET multiplexer card and another card.
 2. A compactenclosure assembly as claimed in claim 1, wherein: the enclosure has twoof said openings therein, the first of which having a larger width thanthe other.
 3. A compact enclosure assembly as claimed in claim 1,wherein: the first opening is capable of receiving a reduced sizeDS1-DS3 multiplexer card.
 4. A compact enclosure assembly as claimed inclaim 1, wherein: the first opening is capable of receiving the reducedsize SONET multiplexer card and a wave division multiplexing card at thesame time.
 5. A compact enclosure assembly as claimed in claim 1,further comprising: a fan mounted to the enclosure.
 6. A compactenclosure assembly as claimed in claim 1, wherein: the compact enclosureassembly attaches to an outside of a support enclosure.
 7. A compactenclosure assembly as claimed in claim 1, wherein: the compact enclosureassembly is received in a larger enclosure.
 8. A compact enclosureassembly as claimed in claim 1, further comprising: a cable fibermanagement assembly coupled to the enclosure to store a cable fiber. 9.A compact enclosure assembly as claimed in claim 1, further comprising:a cable guard coupled at a front end of the enclosure.
 10. A compactenclosure assembly as claimed in claim 1, wherein: the enclosure has aheight of about 5.9 inches, a width of about 4.1 inches, and a depth ofabout 7.3 inches.
 11. A compact enclosure assembly as claimed in claim1, wherein: the enclosure has non dedicated card slots so that plug-incards can be inserted in any available card slot to comply with DS3and/or DS1 requirements of any application.
 12. A compact enclosureassembly as claimed in claim 1, wherein the plurality of openings in theenclosure comprises card slots, and further comprising a plug-in wavedivision multiplexing (WDM) module card configured for insertion in anyavailable card slot in the enclosure and to be grounded upon insertionto perform WDM.